Rotary piston engine



uly 12, 1966 J. GASSMANN ETAL 3,260,247

ROTARY PISTON ENGINE 3 Sheets-Sheet 1 Filed June 8, 1961 IN V EN TORJ' JOHANNES GASSMANN RHARD BRAUN 7 A TT NE Y6 EBE i6; sr

July 12, 1966 J. GASSMANN ETAL 3,260,247

ROTARY PISTON ENGINE Filed June 8, 1961 5 Sheets-Sheet 2 JOHANNES GASSMANN By 555325 BRAUN aw 9 M? y 12, 1966 J. GASSMANN ETAL 3,

ROTARY PISTON ENGINE Filed June 8, 1961 3 Sheets-Sheet 5 N 3 8 INVENTORS'.

JOHANNES GASSMANN EBERHARD BRAUN BY M A ORNEY6 United States Patent 22 Claims. (Cl. 1238) The present invention relates to a rotary-piston internalcombustion-engine of trochoidal construction, and more particularly to such internal combustion engines which are provided with a polygonal piston as internal envelope form within an epitrochoidally-shaped housing which piston carries out a rotary movement about an eccentric member arranged on the driven shaft thereof.

Additionally, the present invention relates to a rotarypiston internal-combustion-engine of the type mentioned hereinabove in which at least one tro'choidally shaped cam surface or cam track is arranged at the housing for purposes of obtaining the desired rotary movement of the piston, and in which the piston is guided along this cam surface or cam track by means of elastically yielding guide roller structures.

In one known prior art internal combustion engine of this type provided with a triangularly-shaped piston within a housing having a two-arched epitrochoid, the planetlike rotary movement of the piston on the eccentric of the output shaft is realized by an externally-toothed and concentrically-arranged gear rigidly secured at the housing which gear meshes with an internally toothed gear wheel rotating together with the piston. In order to attain the rotary velocities of the output shaft and of the piston necessary for practical operation thereof, the number of teeth of the externally toothed gear and the number of teeth of the internally toothed gear wheel must bear to each other a ratio of 2:3. Since with this known controchoidal configuration to the eccentricity e is, within certain limits, predetermined, there is available for the diameter of the output shaft within the stationary gear rigid at the housing only a space which is smaller than four times the value of the eccentricity e.

It has now been discovered that this limitation in the choice of the shaft diameter may be effectively lifted by arranging, according to the present invention, for purposes of achieving the rotary movement of the piston on the eccentric, at least one trochoidally-shaped cam at the housing along which the piston is guided. The ratio of the generating radius for the trochoidal configuration of the cam track to the eccentricity may be thereby selected in such a manner that just sufiicient space remains for the sea-ling ledge members along the side parts of the piston so that shaft diameters may be chosen which enable the operation of the internal combustion engine also as diesel engine or which permit to make relatively large the dimension of the piston in the axial direction thereof. Additionally, it is possible with a construction according to the present invention to subdivide the cam tracks in a simple manner which considerably facilitates the assembly with internal combustion engines in multi-disk construction-s.

According to a further feature of the present inventive concept, the tr-ochoidally-shaped cam track may be arranged, for purposes of achieving the rotary movement, staggered or displaced to the housing trochoid at the necessary transmission ratio. The guidance of the piston along the trochoidally-shaped cam track may take place advantageously by guide rollers arranged at the piston.

.40 struction, the ratio of the generating radius R for the Instead of a single cam track, one cam track each may be arranged at the housing on both sides of the lateral surfaces of the piston. Both cam tracks may be disposed thereby, displaced with. respect to each other, for example, in such a manner that in a housing provided with a twoarched epitrochoid for a triangular piston, the two-arched cam-track epitrochoid for the piston guidance on one side is displaced by to the corresponding cam track at the opposite piston side.

The number of guide rollers belonging to a respective cam track or cam surface may correspond to the number of corners or apices of the piston. The cam tracks may also be arranged on bearing bushings or sleeves which serve for purposes of supporting for the eccentric shaft member within the housing so that the shaft may be sup ported within the housing up to the eccentric member itself. Furtheremore, the guide rollers may be arranged at a bearing ring secured at the piston.

According to a further feature of the present invention the cam track means for guiding the piston in the circumferential direction thereof are subdivided into an internal cam track and into an external cam track whereby the internal cam track is arranged within that peripheral portion of the engine in which the piston is exposed to gaspressure forces. By the use of such an arrangement there is achieved, in an advantageous manner, that even with a very small bearing clearance of the driving shaft within the housing, gas-pressure forces acting on the piston are not transmitted by the piston to the cam track. Additionally, the clearance or play of the piston on the cam track may be reduced thereby to a minimum.

According to still a further feature of the present invention, the transition place from the outer cam track to the inner cam track may be disposed on both sides within the area of the major transverse housing axis. In order that an appropriate and smooth transition of the rollers used for purposes of guidance is achieved from one to the other cam track, the internal cam track may overlap the external cam track at the transition places.

According to still another feature of the present invention, the support of the guide roller structures or the guide roller structures themselves which guide the piston of the internal combustion engine along the cam tracks, may be constructed so 'as to be elastically yielding in the radial direction thereof. It is possible by the use of a guide roller structure according to the present invention to guide the piston practically without play so that all of the guide rollers carry the load and the gas pressures do not load the guide roller structures.

According to one embodiment of the present invention, each of the guide roller structures may consist of an outer and of an inner metallic sleeve between which is arranged an elastically yielding sleeve or bushing, for example, a rubber sleeve or bushing, for instance, vulcanized in situ.

However, according to a modified embodiment of the present invention, each guide roller member structure may be provided with an external contact or runner ring which consists of an elastically yielding material, for example, of a material selected from the general group of polyamides or the like. For purposes of ease of operation and lubrication, the bearing places of the guide roller members may also be provided with floating bushings and may be operatively connected with pressure oil lines.

Accordingly, it is an object of the present invention to provide a rotary-piston internal combustion engine of the type mentioned hereinabove which avoids, in a simple and appropriate manner, the inadequacies and shortcomings of the prior art constructions.

It is another object of the present invention to provide a rotary piston internal combustion engine of trochoidal construction in which the diameter of the output shaft may be chosen from a wider range than possible heretofore.

Another object of the present invention resides in the provision of a drive arrangement including cam means for a rotary piston internal combustion engine of trochoidal construction in which the drive arrangement is so made as to enable use of the engine also as diesel engine and/ or permit pistons of relatively large dimension in the axial direction thereof.

Still a further object of the present invention resides in the provision of a rotary-piston internal combustion engine of trochoidal construction in which the drive arrangement utilizes cam tracks thereby enabling simple assembly, particularly if the engine is of multi-disk construction.

Another object of the present invention resides in the provision of cam surface means to effectively drive the rotary-piston of an internal combustion engine of trochoidal construction which permits the full bearing supports of the shaft carrying the eccentric within the housing of the internal combustion engine.

Still another object of the present invention resides in the provision of cam track guide means for guiding a rotary piston internal combustion engine of trochoidal construction which are so constructed and arranged as to relieve the cam track guide surfaces from any loads caused by gas pressure forces that occur during the operation of the engine.

Still another object of the present invention resides in the arrangement of the cam tracks for guiding a rotarypiston of an internal combustion engine of the type described hereinabove in such a manner as to reduce the clearance of the piston on the cam track surface to a minimum.

A further object of the present invention resides in the provision of guide roller means for guiding the rotary piston during the rotary movement thereof along cam means which are so constructed as to guide the piston for all practical purposes without any clearance to thereby assure substantially uniform as well as simultaneous loading of all guide roller structures while simultaneously therewith relieving the same of gas pressure forces.

These and other objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, several embodiments in accordance with the present invention, and wherein FIGURE 1 is a schematic cross sectional view illustrating the guidance in accordance with the present invention of the rotary piston along a trochoidally-shaped cam track by means of guide roller-members.

FIGURE 2 is an axial longitudinal cross sectional view, on a larger scale, through a rotary piston internal combustion engine in accordance with the present invention, the cross section being taken in the axial direction of the output shaft.

FIGURE 3 is a cross sectional view taken along IIIIII of FIGURE 2;

FIGURE 4 is a schematic cross sectional view, similar to FIGURES 1 and 3 of a modified embodiment of the cam tracks in accordance with the present invention,

FIGURE 5 is a partial cross sectional view, on an enlarged scale, of a guide roller structure in accordance with the present invention, taken along line VV of FIG- URE 1,

FIGURE 6 is a partial cross sectional view, similar to FIGURE 2, illustrating a modified embodiment of a rotary piston internal combustion engine in accordance with the present invention in which the trochoidally shaped cam tracks are provided on the piston and the guide rollers are carried by the housing, and

FIGURE 7 is a schematic cross sectional view, similar to FIGURE 1 and illustrating the guidance in accordance with the present invention of the piston along the cam 4 track by means of the guide roller members as illustrated in FIGURE 6.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate corresponding parts, and more particularly to FIG- URE 1, the rotary-piston internal combustion engine includes a stationary housing generally designated by reference numeral 10, a rotary piston generally designated by reference numeral 20 and rotating within the housing 11). The rotary piston 20 is guided in the rotary movements thereof within the housing 10 by means of guide roller structures generally designated by reference numeral 30, arranged on both sides of the piston structure 20 to guide the piston along trochoidally shaped cam tracks generally designated by reference numeral 40. The cam tracks 40 are arranged at the housing side Walls in any suitable manner whereby a rotary movement is imparted by such guidance to the piston 10 about an eccentric member arranged at the drive shaft as will appear more fully hereinafter.

Referring now in particular to FIGURES 2 and 3, the illustrated rotary-piston internal combustion engine essentially consists of the housing generally designated by reference numeral 10 which includes the two side parts 11 and 12 and the center part 13, of the drive shaft 16 provided with the eccentric 17 which is supported within the housing side parts 11 and 12 by means of bearings 14 and 15 (FIGURE 2) of any appropriate construction, and of the piston generally designated by reference numeral 20 and including a rotating piston member 21 of essentially triangular configuration (FIGURE 3), i.e., provided with apices 22, 23 and 24. As is particularly clearly visible from FIGURE 3, the housing center part 13 is provided with an internal wall 13 shaped in the manner of a twoarched epitrochoid having a major transverse axis 18.

In order to attain a rotary movement of the piston member 21 about the eccentric member 17 on the shaft 16 with /a the angular velocity of the shaft 16, there are provided on both sides of the piston member 21, in place of the usual gear drive including an externally toothed spur gear and an internally toothed gear wheel, cam tracks 41 and 42 on the bearing sleeves 14 and 15 (FIG- URE 2). The cam tracks 41 and 42 are formed, like the two-arched epitrochoids within the housing center part 13, also according to a two-arched epitrochoid by the use of an identical eccentricity with different generating radius (FIGURE 3). The piston member 21 is guided along the cam tracks 41 and 42 by means of guide roller members 31 supported on both sides of a piston member 21 in bearing rings 32, whereby there are provided for each cam track 41 or 42, corresponding to the number of corners or apices 22, 23, 24 of the piston member 21, three guide roller members 31.

In operation, upon rotation of the piston member 21 in the direction of arrow A (FIGURE 3) about the eccentric 17 of shaft 16, the guide roller members 31 roll off along the cam tracks 41 and 42 and guide the piston member 21 with the necessary angular velocity in such a manner that the corners or apices 22, 23 and 24 of the piston member 21 abut with the seals arranged thereat (not illustrated in the drawing) against the two-arched epitrochoidal internal wall 13' of the center housing part 13.

If, as is clearly visible from FIGURE 2, one cam track each is secured at the housing 10 on both sides of the piston member 21, then the major axis of one cam track may be displaced with respect to the major axis of the opposite cam track, in the illustrated embodiment appropriately by In general, it would be sufficient if only one cam track is provided along one piston side the major axis of which is displaced appropriately by 90 with respect to the major axis of the housing epitrochoid.

In the illustrated embodiment of FIGURES 2 and 3, the cam tracks 41 and 42 are arranged directly on the bearing bushings 14 and 15 which, for reasons of weightsavings, are provided at the places of the arcs with cut-out portions or apertures 43. In the alternative, the cam tracks 41 and 42 may also be arranged, without great expenditures or difiiculties, directly within the housing parts 11 and 12.

According to FIGURE 2, the cam tracks 41 and 42 according to the present invention enable for purposes of guiding the piston member 21 by means of the guide rollers 31 the selection of the diameter d for the shaft 16. If gear wheels were used, the pitch circle of the externally toothed gear rigidly connected at the housing would assume, for purposes of achieving the required transmission ratio bet-ween the piston member 21 and the shaft 16, the diameter d so that the shaft diameter would have to be selected smaller than such pitch diameter d and, therefore, would have to be selected considerably smaller than the actual diameter permitted by the arrangement in accordance with the present invention.

A particularly appropriate arrangement of the cam tracks in relation to the guide rollers is illustrated in the embodiment of FIGURE 4. In this embodiment, the housing schematically illustrated therein is again generally designated by reference numeral and the rotary piston rotating in the direction of arrow A is again generally designated therein by reference numeral 20. The rotary piston is guided on both sides of piston 20 by means of guide rollers generally designated by reference numeral along trochoidally-shaped cam tracks generally designated by reference numeral Again, the particular guidance illustrated in FIGURE 4 imparts to the piston 20 a rotary movement about an eccentric similar to eccentric 17 arranged on the shaft 16, as illustrated in connection with FIGURES 2 and 3.

There is provided in the embodiment of FIGURE 4, in a manner similar to that illustrated in FIGURES 2 and 3 on each side of the housing 10, a cam track generally designated by reference numeral 40' which is subdivided into an outer cam track portion 41' and an inner cam track portion 42'. The transition places 44 and between these two cam tracks 41 and 42 are disposed on both sides within the region of the major transverse housing axis 18. Furthermore, the transition places 44 and 45 are so constructed that the internal cam track 42' overlaps the external cam track 41'. The internal can track 42' is additionally located within that circumferential area in which the piston 20 is exposed to gaspressure forces, i.e., the internal cam tarck 42' is adjacent to the combustion space enclosed between the housing 10 and the piston surface 25 in which the ignition of the fuel-air mixture takes place, either through auto-ignition or external ignition.

It is quite clear from FIGURE 4 that the piston 20 cannot transmit the gas-pressure forces prevailing within the combustion space 50, even with a very small bearing clearance of the driving shaft 16 within the housing 10, through the guide rollers 30 to the internal cam track 42, and of course also cannot transmit these forces to the external cam track 41' so that these cam tracks are substantially completely relieved of such forces even with such relatively small play of the drive shaft 16 within the housing 10.

FIGURE 5 which is a cross sectional view, on an enlarged scale, taken through a guide roller generally designated in FIGURE 1 by reference numeral 30, illustrates a preferred construction thereof which essentially consists of an outer metallic sleeve 34, of an inner metallic sleeve 35 and of a rubber bushing 36 arranged between the sleeves 34 and 35 and suitably secured thereto, for example, by vulcanizing in situ. Each guide roller structure 30 is supported on the bolt member 37 by means of a floating bushing 38 which in turn is arranged within the guide ring 32. Within the bolt member 37 is provided a line 39 through which the pressure oil reaches the bearing places of the guide roller structure 30.

FIGURE 6 illustrates an arrangement, similar to FIGURE 1, but modified to the extent that the cam track generally designated again by reference numeral 40 is provided in the end faces of the piston 20 while the guide rollers again generally designated by reference numeral 30 and including guide roller members 31 supported in bearing rings 32 are secured in the side walls 11 and 12 of the housing 10. Similar reference numerals are used in FIGURE 6 to designate corresponding parts of FIGURES l and 2. Furthermore, the details of construction of the various parts may be made as disclosed in FIGURES 2 through 5.

The advantages resulting from the present invention with a construction providing a guidance of the piston in rotary-piston internal-combustion-engines on separate cam tracks are equally obtainable if the cam tracks or cam surfaces are arranged at the piston and the guide rollers cooperating therewith are supported at the hous ing.

While we have shown and described several embodiments in accordance with the present invention, it is understood that the same is not limited thereto, but is susceptible of many changes and modifications within the spirit and scope thereof, and we, therefore, do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

We claim:

1. In a rotary piston-internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the engine shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting said rotary movement to said piston including at least approximately trochoidallyshaped cam means separate from said epitrochoidally shaped internal surfaces and cam follower means cooperating with said c-am means, said cam means being arranged at one of the two parts consisting of said housing and said piston, and said cam follower means being ar-' ranged at the other of said two parts.

2. In a rotary piston-internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the engine shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of at least one approximately trochoidally-shaped cam means arranged in said housing within the area of the piston end face along which said piston is guided for obtaining said rotary movement, the trochoidallyshaped cam means being arranged displaced with respect to the trochoid of said housing.

3. In a rotary piston-internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surf-aces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the engine shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting said rotary movement to said piston including trochoidally-shaped cam means arranged at said housing and guide means including a plurality of guide roller structures arranged at said piston and cooperating with said cam means to thereby guide said piston along said cam means.

4. In a rotary piston-internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the engine shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting said rotary movement to said piston including trochoidally shaped cam means arranged at said housing and guide means including a plurality of guide roller structures arranged at said piston and cooperating with said cam means to thereby guide said piston along said cam means, said cam means including a cam struc-- ture each on both sides of the lateral surfaces of said piston.

5. In a rotary piston-internal combustion engine of trochoidal construction including a housing provided with epitrochoidally-shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the engine shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting said rotary movement to said piston including trochoidally-shaped cam means arranged at said housing and guide means including a plurality of guide roller structures arranged at said piston and cooperating with said cam means to thereby guide said piston along said cam means, said cam means including a cam structure each on both sides of the lateral surfaces of said piston, and said two cam structures being displaced with respect to each other.

6. In a rotary piston-internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the engine shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting said rotary movement to said piston including trochoidally-shaped cam means arranged at said housing and guide means including a plurality of guide roller structures arranged at said piston and cooperating with said cam means to thereby guide said piston along said cam means, said cam means being displaced with respect to the housing trochoid, said cam means including a cam structure each on both sides of the lateral surfaces of said piston, and said two cam structures being displaced with respect to each other.

7. In a rotary piston-internal combustion engine of trochoidal construction having a housing provided with two-arched epitrochoidally shaped internal surfaces defining a chamber and including inlet and outlet means, a three-cornered piston carrying out a rotary movement within said chamber about an eccentric arranged on the drive shaft substantially as internal envelope of the twoarched epitrochoid of the internal surfaces, the improvement essentially consisting of means of imparting said rotary movement to said piston including a two-arched epitrochoidally-shaped cam assembly arranged at said housing, said cam assembly including one cam structure on each side of the lateral surfaces of said piston, and guide means arranged on said piston including a plurality of guide structures cooperating with said cam structures for guiding said piston during such rotary movements, the cam structure on one of said sides being displaced substantially by 90 to the corresponding cam structure on the other side.

8. In a rotary piston-internal combustion engine of trochoidal construction having a housing provided with two-arched epitrochoidally shaped internal surfaces defining a chamber and including inlet and outlet means, a three-cornered piston carrying out a rotary movement within said chamber about an eccentric arranged on the drive shaft substantially as internal envelope of the twoarched epitrochoid of the internal surfaces, the improvement essentially consisting of means for imparting said rotary movement to said piston including a two-arched epitrochoidally-shaped cam assembly arranged at said housing, said cam assembly including one cam structure on each side of the lateral surfaces of said piston, and guide means arranged on said piston including a plurality of guide structures cooperating with said cam structures for guiding said piston during such rotary movements, the cam structure on one of said sides being displaced substantially by to the corresponding cam structure on the other side, the number of guide roller structures corresponding to the number of corners on said piston.

9. A rotary piston-internal combustion engine of trochoidal construction, comprising housing means provided with epitrochoidally shaped internal surfaces defining a chamber and including inlet and outlet means, shaft means provided with eccentric means within said chamber, piston means operable to carry out a rotary movement about said eccentric means within said chamber, said piston means having a plurality of corners and rotating within said epitrochoidally-shaped housing means as internal envelope of the epitrochoid of said internal surfaces, and means for imparting to said piston means said rotary movement including trochoidally-shaped cam means arranged at one of the two parts consisting of said.

piston means and housing means, and guide roller means cooperating with said cam means arranged at the other of said two parts.

10. A rotary piston-internal combustion engine of trochoidal construction, comprising housing means provided with epitrochoidally shaped internal surfaces defining a chamber and including inlet and outlet means, shaft means provided with eccentric means within said chamber, piston means operable to carry out a rotary movement about said eccentric means within said chamber, said piston means having a plurality of corners and rotating within said epitrochoidally-shaped housing means as internal envelope of the epitrochoid of said internal surfaces, and means for imparting to said piston means said rotary movement including trochoidally-shaped cam means arranged at one of the two parts consisting of said piston means and housing means, and guide roller means cooperating with said cam means arranged at the other of said two parts, the number of guide roller means corre sponding to the number of corners of said piston means.

11. In a rotary piston internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the drive shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting to said piston said rotary movement including cam means arranged at one of the two parts consisting of said housing and said piston, and guide roller means arranged at the other of said two parts, said cam means being subdivided effectively into an internal cam track and an external cam track, said internal cam track being arranged within the circumferential area in which said piston is exposed during operation of said engine to gas-pressure forces.

12. In a rotary piston-internal combustion engine of trochoidal construction having a housing provided with twoarched epitrochoidally shaped internal surfaces defining a chamber and including inlet and outlet means, a three-cornered piston provided with bearing ring means and carrying out a rotary movement within said chamber about an eccentric arranged on the drive shaft as internal envelope of the two-arched epitrochoid of said internal surfaces and bearing bushing means for supporting said drive shaft in said housing, the improvement essentially consisting of means for imparting said rotary movement to said piston including a two-arched epitrochoidally-shaped cam assembly arranged at said bearing bushing means, said cam assembly including one cam structure on each side of the lateral surfaces of said piston, and guide means arranged on the bearing ring means of said piston including a plurality of guide structures cooperating with said cam structures for guiding said piston during such rotary movements, the cam structure on One of said sides being displaced substantially by 90 to the corresponding cam structure on the other side, the number of guide roller structures corresponding to the number of corners on said piston.

13. In a rotary piston internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the drive shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting to said piston said rotary movement including cam means arranged at one of the two parts consisting of said housing and said piston, and guide roller means arranged at the other of said two parts, said cam means being subdivided effectively into an internal cam track and an external cam track, said internal cam track being arranged within the circumferential area in which said piston is exposed during operation of said engine to gas-pressure forces, the transition places from said external cam track to said internal cam track being located on both sides within the area of the major transverse axis of said housing.

14. In a rotary piston internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the drive shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting to said piston said rotary movement including cam means arranged at one of the two parts consisting of said housing and said piston, and guide roller means arranged at the other of said two parts, said cam means being subdivided effectively into an internal cam track and an external cam track, said internal cam track being arranged within the circumferential area in which said piston is exposed during operation of said engine to gas-pressure forces, the transition places from said external cam track to said internal cam track being located on both sides within the area of the major transverse axis of said housing, and said internal cam track overlapping said external cam track.

15. A rotary piston-internal combustion engine of trochoidal construction, comprising housing means provided with epitrochoidally shaped internal surfaces defining a chamber and including inlet and outlet means, shaft means provided with eccentric means within said chambenbearing bushing means for supporting said shaft means within said housing means, piston means adapted to carry out a rotary movement about said eccentric means within said chamber, said piston means having a plurality of corners and rotating within said epitrochoidally-shaped housing means as internal envelope of the epitrochoid of said internal surfaces, bearing ring means secured at said piston means, and means for imparting to said piston means said rotary movement including t-r-ochoidally-shaped cam means arranged at said bearing bushing means, and guide roller means elastically yielding in the radial direction thereof and cooperating with said cam means arranged at said bearing ring means, said cam means being subdivided into internal and external cam track structures subdivided essentially within the area of the major transverse axis of said housing means, said internal and external cam track structures overlapping within the areas of transition, and said internal cam track structure being arranged within the circumferential area in which said piston means is exposed to gas pressure forces.

16. A rotary piston-internal combustion engine of trochoidal construction, comprising housing means provided with epitrochoidally shaped internal surfaces defining a chamber and including inlet and outlet means, shaft means provided with eccentric means within said chamber, bearing bushing means for supporting said shaft means within said housing means, piston means adapted to carry out a rotary movement about said eccentric means within said chamber, said piston means having a plurality of corners and rotating within said epitrochoidally-shaped housing means as internal envelope of the epitrochoid of said -inter-, nal surfaces, bearing ring means secured at said piston means, and means for imparting to said piston means said rotary movement including trochoidally-shaped cam means arranged at said bearing bushing means, and guide roller means elastically yielding in the radial direction thereof and cooperating with said cam means arranged at said bearing ring means, said guide roller means including floating bushing means and oil-pressure lubricating means, said cam means being subdivided into internal and external cam track structures subdivided essentially within the area of the major transverse axis of said housing means, said internal and external cam track structures overlapping within the areas of transition, and said internal cam track structure being arranged within the circumferential area in which said piston means is exposed to gas pressure forces.

17. In a rotary piston-internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the drive shaft substantially as inter-nal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting said rotary movement to said piston including trochoidally-shaped cam means and guide means cooperating with said cam means, said cam means being arranged at one of the two parts consisting of said housing and said piston and said guide means being arranged at the other of said two parts, said guide means including a plurality of guide roller structures which eifectively are elastically resilient in the radial direction thereof.

18. In a rotary piston-internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the drive shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting said rotary movement to said piston including trochoidally-shaped cam means and guide means cooperating with said cam means, said cam means being arranged 'at one of the two parts consisting of said housing and said piston and said guide means being arranged at the other of said two parts, said guide means including a plurality of guide roller structures which effectively are elastically resilient in the radial direction thereof, each guide roller structure including an outer sleeve, an inner sleeve and an elastic sleeve intermediate said inner and outer sleeves and secured therebetween.

19. In a rotary piston-internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the drive shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting said rotary movement to said piston including trochoidally-shaped cam means and guide means cooperating with said cam means, said cam means being arranged at one of the two parts consisting of said housing and said piston and said guide means being arranged at the other of said two parts, said guide means including a plurality of guide roller structures which effectively are elastically resilient in the radial direction thereof, each guide roller structure including an outer contact ring made of an elastically yielding material.

20. In 'a rotary piston-internal combustion engine of trochoidal construction including a housing provided with epitrochoidally shaped internal surfaces defining a chamber and having inlet and outlet means, a polygonal piston carrying out a rotary movement within said chamber about an eccentric arranged on the drive shaft substantially as internal envelope of the epitrochoid of said internal surfaces, the improvement essentially consisting of means for imparting said rotary movement to said piston including trochoidally-shaped cam means and guide means cooperating with said cam means, said cam means being arranged at one of the two parts consisting of said housing and said piston and said guide means being arranged at the other of said two parts, said guide means including a plurality of guide roller structures which effectively are elastically resilient in the radial directionthereof, and the bearing places of said guide roller structures being provided with floating bushing means and being operatively connected with pressure oil lines.

21. In a rotary piston-internal combustion engine or trochoidal construction having a housing provided with two arched epitrochoidally shaped internal surfaces defining a chamber and including inlet and outlet means, a three-cornered piston provided with bearing ring means and carrying out a rotary movement within said chamber about an eccentric arranged on the drive shaft as internal envelope of the two-arched epitrochoid of said internal surfaces, and bearing bushing means for supporting said drive shaft in said housing, the improvement essentially consisting of means for imparting said rotary movement to said piston including a two-arched epitrochoidallyshaped cam assembly subdivided into external and internal cam track surfaces and arranged at said bearing bushing means, the internal cam track surfaces being arranged within the circumferential area in which said piston is exposed to gas-pressure forces, said cam assembly including one cam structure on each side of the lateral surfaces of; said piston, and guide means arranged on the bearing ring means of said piston including three guide roller structures operable to effectively yield elastically in the radial direction thereof and cooperating with said cam structures for guiding said piston during such rotary movements, the cam structure on One of said sides being displaced substantially by 90 to the corresponding cam structure on the other side.

22. A rotary piston-internal combustion engine of trochoidal construction, comprising housing means provided with epitrochoidally shaped internal surfaces defining a chamber and including inlet and outlet means, shaft means provided with eccentric means within said chamber, piston means operable to carry out a rotary movement about said eccentric means within said chamber, said piston means having a plurality of corners and rotating within said epitrochoidally-shaped housing means as internal envelope of the epitrochoid of said internal surfaces, and means for imparting to said piston means said rotary movement including trochoidally-shaped cam means arranged at said housing means, and guide roller means elastically yielding in the radial direction thereof and cooperating with said cam means arranged at piston means.

References Cited by the Examiner UNITED STATES PATENTS 2,988,065 6/1961 Wankel et a1 123-8 3,096,746 7/1963 Sollinger 123-8 SAMUEL LEVINE, Primary Examiner.

RALPH H. BRAUNER, JOSEPH H. BRANSON, 111.,

Examiners.

F. T. SADLER, Assistant Examiner. 

1. IN A ROTARY PISTON-INTERNAL COMBUSTION ENGINE OF TROCHOIDAL CONSTRUCTION INCLUDING A HOUSING PROVIDED WITH EPITROCHOIDALLY SHAPED INTERNAL SURFACES DEFINING A CHAMBER AND HAVING INLET AND OUTLET MEANS, A POLYGONAL PISTON CARRYING OUT A ROTARY MOVEMENT WITHIN SAID CHAMBER ABOUT AN ECCENTRIC ARRANGED ON THE ENGINE SHAFT SUBSTANTIALLY AS INTERNAL ENVELOPE OF THE EPITROCHOID OF SAID INTERNAL SURFACES, THE IMPROVEMENT ESSENTIALLY CONSISTING OF MEANS FOR IMPARTING SAID ROTARY MOVEMENT TO SAID PISTON INCLUDING AT LEAST APPROXIMATELY TROCHOIDALLYSHAPED CAM MEANS SEPARATE FROM SAID EPITROCHOIDALLY SHAPED INTERNAL SURFACES AND CAM FOLLOWER MEANS COOPERATING WITH SAID CAM MEANS, SAID CAM MEANS BEING ARRANGED AT ONE OF THE TWO PARTS CONSISTING OF SAID HOUSING AND SAID PISTON, AND SAID CAM FOLLOWER MEANS BEING ARRANGED AT THE OTHER OF SAID TWO PARTS. 